# Selenate selenite

A selenate selenite is a chemical compound or salt that contains selenite and selenate anions (SeO$_3$$^{2-}$ and SeO$_4$$^{2-}$). These are mixed anion compounds. Some have third anions.

## Naming

A selenate selenite compound may also be called a selenite selenate.

## Production

One way to produce a selenate selenite compound is to evaporate a water solution of selenate and selenite compounds.

## Properties

On heating, selenate selenites lose SeO$_2$ and O$_2$ and yield selenites, and ultimately metal oxides.

## Related

Related to these are the sulfate sulfites and tellurate tellurites. They can be classed as mixed valent compounds.

## List

| name | formula | ratio SeO$_4$:SeO$_3$ | mw | system | space group | unit cell Å | volume | density | properties |
| Boroseleniteselenate | B$_2$Se$_3$O$_{10}$ | 1:2 | | monoclinic | P2$_1$/c | a = 4.3466, b = 7.0237, c = 22.1460, β = 94.922°, Z = 4 | | | colourless hygroscopic |
| | Na$_2$(SeO$_4$)(H$_2$SeO$_3$)· H$_2$O | 1:1 | | orthorhombic | Cmc2$_1$ | a=9.615, b=11.19, c=9.62 Z=4 | | | |
| | Sc$_2$(SeO$_3$)$_2$(SeO$_4$) | 1:2 | | monoclinic | P2$_1$/c | a = 6.5294, b = 10.8557, c = 12.6281, β = 103.543° Z = 4 | 870.21 | | |
| | Sc$_2$(TeO$_3$)(SeO$_3$)(SeO$_4$) | 1:1 | | monoclinic | P2$_1$/c | a = 6.535, b = 10.970, c = 12.559, β = 102.70° Z = 4 | 878.3 | | |
| | Fe(SeO$_4$)(HSeO$_3$)· H$_2$O | 1:1 | | monoclinic | P2$_1$/c | a=8.355,b=8.696,c=9.255, β=93.72°,Z=4 | 670.95 | | |
| Lithium sequicopper selenite selenate | Li$_2$Cu$_3$(SeO$_3$)$_2$(SeO$_4$)$_2$ | 2:2 | | monoclinic | I2/a | a=16.293,b=5.007,c=14.448, β = 94.21°, Z=4 | 1175.5 | | |
| | RbFe(SeO$_3$)(SeO$_4$) | 1:1 | | | | a=5.339, c=41.206, Z=6 | 1040.2 | | |
| | Y$_2$(SeO$_3$)$_2$(SeO$_4$)(H$_2$O)$_2$·(H$_2$O)$_{0.75}$ | 1:2 | | monoclinic | C2/c | a=11.9118 b=6.8886 c=12.9644 β=103.839° | | | UV cut off 211 nm |
| | Zr(SeO$_3$)(SeO$_4$) | 1:1 | | orthorhombic | Pbca | a = 8.291, b = 9.458, c = 15.357, Z = 8 | 1204.2 | | |
| | Zr$_4$(SeO$_3$)(SeO$_4$)$_7$ | 7:1 | | monoclinic | P2$_1$/n | a = 5.313, b = 10.704, c = 10.484, β = 104.13°, Z = 1 | 578.2 | | |
| | Zr$_3$(SeO$_3$)(SeO$_4$)$_5$·2H$_2$O | 5:1 | | triclinic | P1 | a = 5.273, b = 8.079, c = 11.959, α = 82.60°, β = 88.27°, γ = 89.87°, Z = 1 | 505.1 | | |
| | Ag$_4$(Mo$_2$O$_5$)(SeO$_4$)$_2$(SeO$_3$) | 2:1 | | orthorhombic | Pbcm | a=5.6557, b=15.8904, c=15.7938, Z=4 | 1419.4 | | |
| tricadmium(II) bis-[selenite(IV)] selenate(VI) | Cd$_3$(SeO$_3$)$_2$(SeO$_4$) | 1:2 | | monoclinic | P2$_1$ | a=8.302 b=5.337 c=10.843 β =108.641 Z=2 | 876.32 | 4.539 | SHG 0.6×KDP; stable to 482 °C |
| | (NH$_4$)$_4$Cd(HSe$^{IV}$O$_3$)$_2$(Se$^{VI}$O$_4$)$_2$ | 2:2 | | triclinic | P1 | a = 5.791 b = 7.411 c = 10.736 α = 90.05° β = 105.02° γ = 112.61° | 408.2 | | |
| | La$_2$(HSeO$_3$)(SeO$_4$)· 2H$_2$O | 1:1 | | monoclinic | P2$_1$/n | a=7.272 b=9.409 c=11.940 β =93.32° | | | |
| | NaLa(SeO$_3$)(SeO$_4$) | 1:1 | | monoclinic | P2$_1$/c | a=10.751 b=7.098 c=8.437 β =90.90° | | | |
| | Pr$_4$(SeO$_3$)$_2$(SeO$_4$)F$_6$ | 1:6 | | monoclinic | C2/c | a = 22.305, b = 7.1054, c = 8.356, β = 98.05°, Z = 4 | | | light green |
| dineodymium diseleite selenate | Nd$_2$(SeO$_3$)$_2$(SeO$_4$) · 2H$_2$O | 1:2 | 721.39 | monoclinic | C2/c | a = 12.276, b = 7.0783, c = 13.329, β = 104.276° | 1122.4 | 4.27 | pink |
| | NaSm(SeO$_3$)(SeO$_4$) | 1:1 | | monoclinic | P2$_1$/c | a = 10.669, b = 6.9166, c = 8.2588, β = 91.00° Z = 4 | | | light yellow |
| | Er$_2$(SeO$_3$)$_2$(SeO$_4$) · 2H$_2$O | 1:2 | | monoclinic | C2 | a=11.935 b=6.881 c=6.473 β =103.79° Z=4 | | | |
| | Hf(SeO$_3$)(SeO$_4$)(H$_2$O)$_4$ | 1:1 | | | | | | | |
| | Au$_2$(SeO$_3$)$_2$(SeO$_4$) | 1:2 | | orthorhombic | Cmc2$_1$ | a = 16.891, b = 6.3013, c = 8.327, Z = 4 | 886.2 | | orange yellow |
| | Hg$_3$(SeO$_3$)$_2$(SeO$_4$) | 1:2 | | monoclinic | P2$_1$ | a = 8.3979 b = 5.3327 c = 11.148 β = 108.422° Z = 2 | 473.67 | | colourless |
| | Hg$_3$Se(SeO$_3$)(SO$_4$) | | | monoclinic | P2$_1$/n | a=7.1188 b=9.9209 c=12.4565 β=95.398° Z=4 | 875.84 | 6.854 | colourless; band gap 3.5 eV; birefringence 0.069@546 nm |
| | Hg$_5$O(SeO$_3$)(SeO$_4$) | 1:1 | 1288.87 | | C2/c | a=17.563 b=6.188 c=18.912 β =90.379 Z=8 | 2055.2 | 8.331 | yellow |
| | Hg$_3$Hg$_2$Hg(HgO$_2$)(SeO$_3$)$_2$(SeO$_4$)·H$_2$O | 1:2 | | | R3 | a=5.9239 c=37.096 Z=3 | | | |
| | Hg$_3$Hg$_2$Hg$_2$(HgO$_2$)(SeO$_3$)$_2$(SeO$_4$)$_2$·H$_2$O | 2:1 | | | P3$_1$c | a=5.8908 c=31.048 Z=2 | | | |
| | Ag$_4$Hg(SeO$_3$)$_2$(SeO$_4$) | 1:2 | 1028.95 | orthorhombic | Cmc2$_1$ | a=8.1690 b=11.9903 c=10.8870 Z=4 | 1066.4 | 6.409 | 398 nm cutoff NLO 0.35×KDP |
| | Pb$_2$(SeO$_3$) (SeO$_4$) | 1:1 | 684.30 | orthorhombic | Pnma | a=13.5080 b=5.6238 c=9.2706 Z=4 | 704.25 | 6.454 | stable to 232 °C |
| schmiederite | Pb$_2$Cu$_2$(OH)$_4$(SeO$_3$)(SeO$_4$) | 1:1 | | monoclinic | P2$_1$/m | a = 9.922, b = 5.712, c = 9.396, β = 101.96°, Z = 2 | | | |
| | Bi$_2$(SeO$_3$)$_2$(SeO$_4$) | 1:2 | 814.84 | monoclinic | I2/a | a= 8.0440 b=7.4377 c=14.7456 β =97.274 Z=4 | 875.11 | 6.184 | colourless |
| | Ag$_2$Bi$_2$(SeO$_3$)$_3$(SeO$_4$) | 1:3 | 1157.54 | monoclinic | P2$_1$/m | a=9.5380 b=5.4965 c=11.8207 β =92.892 Z=2 | 618.92 | 6.211 | 339 nm cutoff |
| | Th(SeO$_3$)(SeO$_4$) | 1:1 | | monoclinic | P2$_1$/c | a=7.0351 b=9.5259 c=9.02266 β =103.128, Z=4 | | | |
| | (H$_3$O)[(UO$_2$)(SeO$_4$)(SeO$_2$OH)] | 1:1 | | monoclinic | P2$_1$/n | a = 8.668, b = 10.655, c = 9.846, β = 97.88° | 900.7 | | |
| | [C$_5$H$_{14}$N][(UO$_2$)(SeO$_4$)(SeO$_2$OH)] | 1:1 | | monoclinic | P2$_1$/n | a=11.553, b=10.645, c=12.138, β=108.05, Z=4 | | | |
| | [C$_5$H$_{14}$N]$_4$[(UO$_2$)$_3$(SeO$_4$)$_4$(HSeO$_3$)(H$_2$O)]·(H$_2$SeO$_3$)(HSeO$_4$) | 5:2 | | triclinic | P1 | a = 11.7068, b = 14.816, c = 16.977, α = 73.899°, β = 76.221°, γ = 89.361°, Z = 2 | 2743.0 | | |
| catena-(bis(Dimethylammonium) oxonium tetrakis(μ$_3$-selenato)-(μ$_2$-selenito)-aqua-hexaoxo-tri-uranium selenous acid) | [C$_2$H$_8$N]$_2$[H$_3$O][(UO$_2$)$_3$(SeO$_4$)$_4$(HSeO$_3$)(H$_2$O)](H$_2$SeO$_3$)$_{0.2}$ | 4:1.2 | | monoclinic | P2$_1$/m | a 8.3116 b 18.6363 c 11.5623 β =97.582° | | | |
| catena-(tris(Dimethylammonium) tetrakis(μ$_3$-selenato)-(μ$_2$-hydrogen selenito)-aqua-hexaoxo-tri-uranium dimethylamine) | [C$_2$H$_8$N]$_3$(C$_2$H$_7$N)[(UO$_2$)$_3$(SeO$_4$)$_4$(HSeO$_3$)(H$_2$O)] | 4:1 | | orthorhombic | Pnma | a =11.659 b =14.956 c =22.194 | | | |
| | [NH$_3$(CH$_2$)$_9$NH$_3$][(UO$_2$)(SeO$_4$)(SeO$_2$OH)](NO$_3$) | 1:1 | | triclinic | P1 | a = 10.7480, b = 13.8847, c = 14.636, α = 109.960°, β = 103.212°, γ = 90.409°, Z= 4 | 1990.0 | | |
| | Cs$_2$(H$_2$O)$_5$[(UO$_2$)$_7$(SeO$_4$)$_2$(SeO$_3$)$_2$O$_4$]. H$_2$O | 2:2 | | monoclinic | P2$_1$/m | a =.1381, b =15.0098, c =15.1732 β=91.17° | | | |